Steering tool

ABSTRACT

A steering tool including an internal tube disposed inside an external tube, the internal and external tubes being arranged for longitudinal axial movement relative to one another, wherein a distal end of the internal tube is fixedly joined to a distal end of the external tube, and at least one of the internal and external tubes is slotted near the distal end thereof, and wherein the longitudinal axial movement causes bending of the distal ends of the tubes.

FIELD OF THE INVENTION

The present invention generally relates to a steering tool for steeringmedical devices through body lumens.

BACKGROUND OF THE INVENTION

As is well known in the art, many medical procedures require steering amedical device through vasculature or other body lumens of a patient.One of the most common methods used involves passing a guidewire throughthe body lumen to a desired location. The medical device, such as acatheter, valve, stent, etc., is positioned by sliding over theguidewire to the desired location.

The lumen traversed by the guidewire can have various bends andbranches. Sometimes, in order for the medical device to negotiate thebends and branches, not only must the guidewire be flexible, but alsothe medical device must have flexibility. However, delivery systemcurvature is not always desirable. Another problem is the device distaltip, which often must be bendable and steerable more than the rest ofthe device, yet the device must be constructed to allow application oftorque to the tip.

SUMMARY OF THE INVENTION

The present invention seeks to provide an improved steering tool forsteering medical devices through body lumens, as is described more indetail hereinbelow. The steering tool solves the abovementioned problemsby providing a distal tip which combines steerability, flexibility andtorqueability. The tool eliminates the need for pull/push wires.

One of the advantages of the present invention is its structure reducesthe cross section of prior art steering tools that use push/pull wires.Another advantage is the ability to bend in different directions (atleast two sides can bend and the device can be made for bending in morethan two sides). The wall thickness can be very thin, such as 0.05 mm,but the invention is not limited to any thickness. The invention iseffective for small tubes, such as but not limited to, diameters of0.5-3 mm, and eliminates the need for ˜0.2 mm manipulating wires and anyspace needed for extrusion. The invention is also effective with soft,thick tubes without any need for cutting.

There is thus provided in accordance with an embodiment of the presentinvention a steering tool including an internal tube disposed inside anexternal tube, the internal and external tubes being arranged forlongitudinal axial movement relative to one another, wherein a distalend of the internal tube is fixedly joined to a distal end of theexternal tube, and at least one of the internal and external tubes isslotted near the distal end thereof, and wherein the longitudinal axialmovement causes bending of the distal ends of the tubes.

In accordance with an embodiment of the present invention both of theinternal and external tubes are slotted near the distal ends thereof.

In accordance with another embodiment of the present invention only oneof the internal and external tubes is slotted, and the other tube isflexible, but not slotted.

In accordance with an embodiment of the present invention, for each ofthe tubes, the slots are generally perpendicular to a longitudinal axisof the tube.

In accordance with an embodiment of the present invention open ends ofthe slots of the external tube are oriented towards throats of theinternal tube, and open ends of the internal tube are oriented towardsthroats of the external tube.

In accordance with another embodiment of the present invention, insteadof a slotted tube, one of the tubes is flexible with relatively rigidstiffeners at a distal portion thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description taken in conjunction with thedrawings in which:

FIG. 1A is a simplified illustration of an external tube used in asteering tool, in accordance with a non-limiting embodiment of thepresent invention;

FIG. 1B is a simplified illustration of an internal tube used in thesteering tool, in accordance with a non-limiting embodiment of thepresent invention, wherein both internal and external tubes are slotted;

FIG. 1C is a simplified illustration of the assembled steering tool, inaccordance with a non-limiting embodiment of the present invention;

FIGS. 2A and 2B are simplified illustrations of bending the steeringtool of FIG. 1C;

FIG. 3 is a simplified illustration of a steering tool, in accordancewith another non-limiting embodiment of the present invention, whereinonly one of the internal and external tubes is slotted, and the other isflexible, but not slotted;

FIG. 4 is a simplified illustration of a steering tool, in accordancewith another non-limiting embodiment of the present invention, wherein aslotted tube is replaced by a flexible tube with stiffeners, wherein thestiffeners serve in place of the non-slotted portion and the flexibilityserves in place of the slotted portion;

FIGS. 5A and 5B are simplified illustrations of a steering tool, inaccordance with another non-limiting embodiment of the presentinvention, respectively before and after bending, wherein some of theslots face in different directions; and

FIG. 6 is a simplified illustration of a steering tool, in accordancewith another non-limiting embodiment of the present invention, whereinat least some adjacent slots are circumferentially phase shifted withrespect to each other about the circumference of the tube.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is now made to FIGS. 1 and 2, which illustrate a steering tool10, in accordance with a non-limiting embodiment of the presentinvention.

Steering tool 10 includes an internal tube 12 disposed inside anexternal tube 14. A distal end 12D of internal tube 12 is fixedly joinedto a distal end 14D of external tube 14. The term “joined” encompassesany method for attaching the materials of the tubes together, such asbut not limited to, welding, ultrasonic welding, thermal bonding,adhesive bonding, molding, and others. Internal and external tubes 12and 14 are arranged for longitudinal axial movement relative to oneanother.

Internal and external tubes 12 and 14 may be made of any suitablyflexible, medically safe material, such as but not limited to, stainlesssteel (e.g., AISI 316), nitinol, cobalt-chromium alloy, nickel-titaniumalloy, and others, plastics (e.g., nylon, polypropylene, and manyothers) or combinations thereof.

At least one of the internal and external tubes 12 and 14 is slottedwith slots 16 near the distal end thereof. In the embodiment of FIGS.1A-1C, both tubes are slotted. In the embodiment of FIG. 3, only one ofthe internal and external tubes is slotted (reference numeral 30), andthe other (reference numeral 32) is flexible, but not slotted. Thelongitudinal axial movement causes bending of the distal ends of thetubes, as seen in FIGS. 2A and 2B. As seen in FIG. 2A, one of theinternal and external tubes can be longer than the other (in this case,the internal one is longer for grasping its proximal end for pushing andpulling thereof).

Slots 16 increase the flexibility toward the distal end of the tube ortubes for steerability of the device and controlled manipulationthereof. The amount of flexibility can be controlled by the number ofslots, spacing therebetween, shape of the slot, angle subtended by theslot, thickness of the tube, material of the tube, and other factors.

Each slot 16 has an open end 18. In the illustrated embodiment, slots 16are generally perpendicular to the longitudinal axis 20 of the tube. Inother embodiments, the slots are non-perpendicular to the longitudinalaxis 20 of the tube. The throat 22 of each slot 16 is shown as beingwider than the open end 18. In other embodiments, throat 22 is not widerthan the open end 18.

In the illustrated embodiment, slots 16 subtend an arc of about180-270°, but the invention is not limited to this range. The remainingportion of the tube is left intact, so there is sufficient mechanicalstrength to prevent buckling or other mechanical failure.

In the illustrated embodiment, in the finished assembly of FIG. 1C, theopen ends 18 of the external tube 14 are oriented towards the throats 22of the internal tube 12; conversely, the open ends 18 of the internaltube 12 are oriented towards the throats 22 of the external tube 14. Itis noted that the slots can be oriented at different orientations otherthan that illustrated in FIG. 1C (e.g., the throats and open ends arealigned at different angles and spacings, the slots are shapeddifferently, etc.) to arrive at bending modes in more than one directionin three-dimensional space.

In the illustrated embodiment, the slots are equally spaced, sized andshaped, but other variations in spacing, size and shape can be used toachieve different properties.

Some non-limiting examples of different sizes and arrangements ofslotted portions and non-slotted portions are now described withreference to FIGS. 5A-5B and 6.

In FIGS. 5A-5B, some of the slots 16 have open ends 18 facing in onedirection, while other slots 16 have the open ends 18 facing in anotherdirection, such as 180° apart (although the invention is not limited tothis angle). FIG. 5B shows how the tube bends in such a configuration.

In FIG. 6, slots 16 are axially spaced along the distal portion of thetube, but at least some (or all) adjacent slots 16 are circumferentiallyphase shifted with respect to each other about the circumference of thetube. For example, a first slot may start at some reference point on thecircumference, defined as 0°, whereas the next slot may start at 5° andthe next one at 10°, etc. The phase shift does not have to be equal (canalso be zero for some adjacent slots) and can be ascending, descendingor a combination of both.

Slots 16 can be formed by any suitable method, such as but not limitedto, machining, cutting, etching, laser cutting and others.

Reference is now made to FIG. 4, which illustrates a steering tool 40,in accordance with a non-limiting embodiment of the present invention.In this embodiment, steering tool 40 includes a flexible tube 42 (e.g.,without limitation, made of an extruded material, plastic or metal) withrelatively rigid stiffeners 44 (internal or external) at a distalportion 46. Flexible tube 42 replaces the slotted tube of the previousembodiments. The stiffeners 44 serve in place of the non-slotted portionof the previous tubes, and the flexibility of tube 42 serves in place ofthe slotted portion of the previous tubes.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the features describedhereinabove as well as modifications and variations thereof which wouldoccur to a person of skill in the art upon reading the foregoingdescription and which are not in the prior art.

What is claimed is:
 1. A steering tool comprising: an internal tubedisposed inside an external tube, said internal and external tubes beingarranged for longitudinal axial movement relative to one another,wherein a distal end of said internal tube is fixedly joined to a distalend of said external tube, and at least one of said internal andexternal tubes is slotted near the distal end thereof, and wherein thelongitudinal axial movement causes bending of the distal ends of saidtubes, wherein at least some adjacent slots are circumferentially phaseshifted with respect to each other about a circumference of said atleast one of said internal and external tubes with a phase shift of lessthan 180°.
 2. The steering tool according to claim 1, wherein both ofsaid internal and external tubes are slotted near the distal endsthereof.
 3. The steering tool according to claim 1, wherein only one ofsaid internal and external tubes is slotted, and the other tube isflexible, but not slotted.
 4. The steering tool according to claim 2,wherein at least some adjacent slots of both said internal and externaltubes are circumferentially phase shifted with respect to each other,each with a phase shift of less than 180°.
 5. The steering toolaccording to claim 1, wherein for each of said tubes, said slots aregenerally perpendicular to a longitudinal axis of the tube.
 6. Thesteering tool according to claim 1, wherein a throat of each of saidslots is wider than an open end of each of said slots.
 7. The steeringtool according to claim 1, wherein said slots subtend an arc of about180-270°.
 8. The steering tool according to claim 1, wherein open endsof said slots of said external tube are oriented towards throats of saidinternal tube, and open ends of said internal tube are oriented towardsthroats of said external tube.
 9. The steering tool according to claim1, wherein some of said slots face in different directions.
 10. Thesteering tool according to claim 1, wherein some of said slots are phaseshifted with respect to each other with different phase shifts that areunequal.
 11. The steering tool according to claim 1, wherein some ofsaid slots are phase shifted with respect to each other in ascendingphase shifts.
 12. The steering tool according to claim 1, wherein someof said slots are phase shifted with respect to each other in descendingphase shifts.
 13. The steering tool according to claim 1, wherein someof said slots are phase shifted with respect to each other in ascendingphase shifts and some of said slots are phase shifted with respect toeach other in descending phase shifts.